Milestone for a start-up, for short

IPO

When a private company first offers shares to the public, it’s often called this three-letter event.

This clue refers to a major event in a company's growth when it first offers shares to the public. "For short" signals that the answer is an abbreviation—IPO stands for Initial Public Offering, a common business term. Start-ups often aim for an IPO as a key milestone to raise capital and expand. The clue plays on the idea of a "milestone," which fits both the achievement and the financial step.